.button {
    width: 100%;
    height: 50px;
    display: flex;
    position: fixed;
    bottom: 0;
    background-color: #ccc;
    .btn {
        width: 20%;
        height: 100%;
        text-align: center;
        line-height: 50px;
        background-color:white;
    }
    .color{
         width: 20%;
        height: 100%;
        text-align: center;
        line-height: 50px;
        background-color: gray;
        color: white;
    }
}